The maxillary sinus has a poor drainage system that requires the ciliary transport system to work against gravity. Ciliary activity is slowed or stopped by alterations in temperature, bacterial toxins and other factors such as changes in the pH. The maxillary sinus becomes infected very easily and is the most difficult to clear. All of the other paranasal sinuses are capable of gravity drainage. The maxillary sinus opening however is located high in the nasal sinus above the level of the middle turbinate. Consequently, the maxillary sinus does not cleanse well.
Increased mucus concentration causes a congestion in the nostrils, sinus cavities and ears leading to painful headaches. Sinus fluids which drain by gravity tend to cause irritation of the throat. When excessive mucus is produced because of infection or weather conditions there is much discomfort, thereby affecting a person's daily performance.